1. Technical Field
The present invention relates to a technique of mounting a long cylindrical tank on a vehicle.
2. Description of the Related Art
With recent advancement of fuel cells, fuel cell vehicles have been becoming popular. Hydrogen gas used as a fuel gas of the fuel cells is filled in a high-pressure gas tank, which is mounted on the fuel cell vehicle. Since weight reduction is highly demanded for the tank mounted on the vehicle, the high-pressure gas tank is generally made of a resin material. The high-pressure gas tank made of the resin material is expanded with an increase of the internal pressure of the tank in the gas filling process and is contracted with a decrease of the internal pressure of the tank in the gas consuming process. A tank mounting mechanism disclosed in JP-A 2003-118402 has been proposed by taking into account such characteristics.
The resin tank is expanded and contracted in its longitudinal direction as well as in its radial direction with a variation in internal pressure of the tank. The tank is required to be connected with gas piping after or simultaneously with mounting of the tank on the vehicle. Steel pipes having the high pressure resistance are generally used for such gas piping. It is thus required to position the tank around its longitudinal axis. The tank mounting mechanism disclosed in the above cited reference uses tank shoulders on tank edges to respond to expansion and contraction of the tank in the longitudinal direction. The tank shoulders are, however, naturally affected by the expansion and contraction of the tank. This prior art tank mounting mechanism accordingly has the relatively low reliability and requires further improvement.